The present invention relates to mechanisms for adjusting components of a chair relative to one another, and more particularly to a height adjustment mechanism for chair backrest or arm with improved characteristics.
Conventional height adjustment mechanisms for backrest or arm of a chair are strength dependent and require considerable effort on the part of user to achieve positioning. Further, such prior mechanisms are typically complex in constructions, difficult to assemble, trouble-prone, unreliable, and unsightly. Thus, improvement exists.
It is thus an object of the present invention to provide an adjustment mechanism mounted on a chair for releasably locking one chair component such as backrest or arm in any one of a plurality of positions relative to a seat of the chair, the adjustment mechanism comprising a tube-like brace having one end secured to underside of the seat, a transverse elongate groove, and a plurality of transverse disposed apertures; a sliding member slideable in the brace with an upper end secured to one chair component; a guide member coupled to a lower end of the sliding member having a longitudinal slot; a hook member having a lower end flexibly coupled to the longitudinal slot of the guide member and an upper bent end; a first half-cylindrical member in the brace including an inner space for receiving the sliding member and the hook member, a plurality of alternate recesses and risers on either side, an internal notched member having a plurality of curved members and a longitudinal channel in communication with the curved members; a second half-cylindrical member in the brace including a plurality of alternate recesses and risers matingly snapped to the alternate risers and recesses of the first half-cylindrical member respectively for securing the half-cylindrical members together, two latches in lower and upper openings respectively for frictionally locking the sliding member, an upper hole, a lower hole, and a spring-depressible detent in the lower hole; and a lock pin inserted through the transverse elongate groove and the upper hole to secure the brace and the second half-cylindrical member together; wherein one chair component is operative to push down to cause the bent end to move through the channel and pull up to lock in one of the curved members.
In one aspect of the present invention, one chair component is an arm so that the detent is operative to disengage from one aperture prior to rotating the arm to cause the detent to engage with the other aperture.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.